"The Arenaverse" is the multiverse of my Arena series, which begins with Grand Central Arena. Currently the series has two volumes, Grand Central Arena (often abbreviated as GCA) and Spheres of Influence (often just called Spheres).
The major action in the Arenaverse takes place in roughly the year 2375. There are two primary "universes" or general locations seen in the Arenaverse: the normal universe, the setting's equivalent of our own physical universe, and The Arena itself, which is very, very different indeed. The two are however strongly connected, and -- from what is known thus far -- The Arena exerts considerable influence over our own universe.
In the Solar System of 2375, humanity has approached Utopia as closely as humanity probably can. Efficient solar energy collection, ubiquitous and efficient nano-manufacturing, and high-density power storage has made it possible for everyone in the system to have, not merely the bare minimum for subsistence, but a very comfortable existence, without any dependence on other people for support. Governments have shrunk, not from war but from disuse; human science and entertainment blend with startling results. While there are still occasional bad events, the population of the system is over 55 billion people, with 35 billion on Earth and the rest of them scattered around the Solar System. Artificial intelligences are widespread, to the point that the vast majority of people have an "AISage" -- an artificially intelligent companion, muse, secretary -- with them at all times, usually actually in their headware, as routinely and normally as most people today carry a cell phone.
Despite all advances, however, humanity remains in its original solar system; no successful ventures to other stars have ever been carried out. Dr. Simon Sandrisson believes that he has discovered the key to Faster-Than-Light travel, and creates the vessel Holy Grail to test his theory, carrying a small crew of eight on a test voyage.
But the Sandrisson Drive does not take you to the stars. Not directly. Instead, it takes you to The Arena.
The Arena is one of the largest constructs ever imagined by man: an entire universe enclosed and controlled, an artificial structure somewhere between 16 and 32 light-years in diameter, within which is contained a complete, detailed scale-model of our entire normal-space universe, with each star system represented by a Sphere, roughly 20,000 kilometers in diameter, which itself contains a scale replica of the individual solar system, with all bodies above a certain size represented. Atop each Sphere, however, is a world-sized living diorama, an environment suitable for the lifeforms dominant within the solar system represented by the Sphere. For the Spheres float within, not empty vacuum, but a gargantuan Sky, filled with wind, storms, clouds and dust, living creatures of uncounted worlds and origins.
The Arena has a fixed relationship to the "normal" universe, such that travel within the Arena is, effectively, faster-than-light in ours. If you can travel from your Sphere to another Sphere (a distance that averages, within a galaxy, perhaps a hundred to two hundred thousand kilometers) and activate your Sandrisson Drive again, you will arrive in space near the solar system of that Sphere.
But there are rules to this. The Arena is either, itself, conscious, or is run by Something that has set rules and interprets them for The Arena. A gargantuan AI? A living being? No one knows, but the rules of the Arena are absolute, binding, and -- almost -- impossible to evade, defy, or reinterpret.
Some of the Arena's rules are actually edicts on aspects of the laws of physics and technology. Nuclear power does not function in The Arena -- with the sole exception of the thermonuclear reactors controlled by the group called the Powerbrokers. Artificial Intelligences also do not function in the Arena. And nanotech only functions within strict limits outside of a species' Sphere, mainly for things like maintaining health (medical nanos). How the Arena can do this is not known; the major speculation is that the creators of the Arena, called "Voidbuilders" by most Arenaverse inhabitants, had mastered technology down to the Planck level, allowing them to literally re-write the physical rules of the universe as desired.
The major purpose of these rules, however, is apparently -- for whatever reason -- to force any species that discovers the Sandrisson Drive or equivalent technology to gather at the location called Nexus Arena and interact with the other species who have also arrived in the Arena. There, they learn of other species, and can compete or cooperate with them, again, according to the rules the Arena itself maintains.
Here it is that Captain Ariane Austin, Dr. Simon Sandrisson, Dr. Marc C. DuQuesne, and the rest of the new Faction of Humanity must face a destiny that was set for them perhaps a hundred million years before they were born...